Motor vehicles may be provided with a telematics unit or a head unit that is communicatively coupled to a controller area network (CAN) bus of the vehicle and that communicates through the CAN bus with a variety of electromechanical devices, electronic controllers, and sensors. The telematics unit is a computer system and may provide some vehicle control functionality as well as monitoring of vehicle operating metrics and outside environment metrics. For example, the telematics unit may be a relay for remote operations commands such as door lock and unlock, engine start and engine stop, horns and lights flash, and the like. The telematics unit, in some cases, may provide image processing for rear back-up imaging, for example creating a mirror image of visual data received from back-up cameras. The telematics unit may likewise provide other computing and/or processing functionality such as navigation system functionality and entertainment system functionality.
The telematics unit may comprise a cellular wireless radio transceiver operable for communication via a cellular wireless communication service, for example when a subscription account for cellular wireless communication has been provisioned for the telematics unit by a wireless communication service provider. Remote operation commands may be received by the radio transceiver of the telematics unit, for example from a cell tower. The commands may be originated by an application executing on a mobile phone, for example a mobile phone belonging to an owner of the vehicle. The wireless communication capability of the telematics unit may be used to access diagnostic information from the vehicle or fleet information from a motor pool vehicle or a rental vehicle.